4.1.The ray Class

src/main.rs

@@ -1,10 +1,14 @@
 use write_file_util::{write_image};
 use image::{gen_gradient_ppm_p3, Color};
 use vec3::{Vec3};
+use point::{Point};
+use ray::{Ray};
 
 mod image;
 mod write_file_util;
 mod vec3;
+mod point;
+mod ray;
 
 fn main() {
     let ppm_content = gen_gradient_ppm_p3(400, 225);
@@ -16,8 +20,10 @@ fn main() {
     println!("v: {:#} + {:#} => {:#}", v1, v2, v1 - v2);
     println!("v: {:#} + {:#} => {:#}", v1, v2, v1.dot(v2));
     println!("v: {:#} + {:#} => {:#}", v1, v2, v1.cross(v2));
-
     println!("color: {:#}", Color::new(0.3, 0.4, 1.0).to_color());
+    println!("point: {:#}", Point::new(1.0, 1.0, 1.0));
+    let ray = Ray::new(Point::new(1.0, 1.0, 1.0), Vec3 { x: 0.0, y: 1.0, z: 0.0 });
+    println!("Ray: {:#} => {:#}", ray, ray.at(2.0));
 
     write_image(ppm_content, "./target/test.ppm".to_string())
 }

src/point.rs

@@ -0,0 +1,4 @@
+use crate::vec3;
+
+pub type Point = vec3::Vec3;
+

src/ray.rs

@@ -0,0 +1,35 @@
+use std::fmt;
+use std::fmt::{Display};
+
+use crate::{point::Point, vec3::Vec3};
+
+
+/*
+fn: P(t) = t*b
+*/
+#[derive(Debug)]
+pub struct Ray {
+    point: Point,
+    direction: Vec3
+}
+
+impl Ray {
+    pub fn new(p: Point, direction: Vec3) -> Ray {
+        Ray { point: p, direction: direction }
+    }
+
+    pub fn at(&self, t: f32) -> Point {
+        Point {
+            x: self.point.x + t * self.direction.x,
+            y: self.point.y + t * self.direction.y,
+            z: self.point.z + t * self.direction.z,
+        }
+    }
+}
+
+
+impl Display for Ray {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "O{}x{}", self.point, self.direction)
+    }
+}